Preferably Pb-free and As-free optical glasses with Tg≦500° C.

Abstract

The present invention relates to preferably lead-free and arsenic-free optical glasses, having a refractive index of 1.48≦n d ≦1.56, an Abbe number of 64≦νd≦72, a low transformation temperature (Tg≦500° C.) and good ion exchange properties, as well as good chemical resistance and crystallization stability, and comprising the following composition (in % by weight): SiO 2 53-58 B 2 O 3 11-15 Al 2 O 3 16-20 Na 2 O  0-13 K 2 O  0-13 ΣM 2 O  9-13 F 0.5-4   The glass may additionally contain standard refining agents. The invention also relates to the use of the optical glasses according to the invention in the application areas of imaging, projection, telecommunications, optical communication technology and/or laser technology.

1. Optical glass having a refractive index n d  of 1.48≦n d ≦1.56, an Abbe number ν d  of 64≦ν d ≦72 and a transformation temperature Tg≦500° C., which comprises the following composition (in % by weight):
                                   SiO 2     53-58         B 2 O 3     11-15         Al 2 O 3     16-20         Na 2 O    0-13         K 2 O    0-13         ΣM 2 O    9-13         F   0.5-4.                                      
 
     
     
       2. Optical glass according to  claim 1 , which comprises the following composition (in % by weight):
                                   SiO 2     53-58         B 2 O 3     11-15         Al 2 O 3     16-20         Na 2 O    9-13         F   0.5-4.                                    
 
     
     
       3. Optical glass according to  claim 1  or  2 , which comprises the following composition (in % by weight):
                                   SiO 2     53-56         B 2 O 3     11-15         Al 2 O 3     16-18         Na 2 O   11-13         F   0.5-4.                                    
 
     
     
       4. Optical glass according to  claim 1 , which as refining agents contains the following components (in % by weight):
                                       Sb 2 O 3     0-1   and/or         SnO   0-1   and/or         NaCl   0-1   and/or         SO 4   2−      0-1.                                  
 
     
     
       5. Optical glass according to  claim 1 , which is substantially free of lead. 
     
     
       6. Optical glass according to  claim 1 , which is substantially free of arsenic. 
     
     
       7. An optical element consisting of the optical glass of  claim 1 . 
     
     
       8. Optical glass having a refractive Index n d of  1.48≦n d ≦1.56, an Abbe number ν d  of 64≦ν d ≦72 and a transformatIon temperature Tg≦500° C, which comprises the following composition (in % by weight):
                                   SiO 2     53-58         B 2 O 3     11-15         Al 2 O 3     16-20         Na 2 O    0-13         K 2 O    0-13         ΣM 2 O    9-13         F   0.5-4           Sb 2 O 3      0-1.